It’s a numbers game building an NFL roster. With only 53 available spots in the regular season, teams have to make some hard decisions. That means that when you add new talent through the draft or free agency, you often have to part ways with players. For the Dallas Cowboys, one obvious need this year (as it has been for some time now) is to find a better pass rusher or two. But the team has a pretty large group of players already under contract, with only one of their defensive linemen from 2016 entering free agency.